Diabetic retinopathy is a major cause of blindness in the United States. Upregulation of adhesion molecules, chemokines, nitric oxide synthase (NOS2), inducible cyclooxygenase (COX-2) and vascular endothelial growth factor (VEGF) are pro- inflammatory responses believed to be important in this disease. It is increasingly recognized that these responses contribute to retinal injury and neuro-vascular degeneration. Understanding the regulation of these responses is important because neuronal death largely contributes to visual loss in diabetic retinopathy and currently available treatment regimens have not been able to prevent neuronal loss. The objective of this application is to further our understanding of the regulation of pro-inflammatory responses and neuro-vascular degeneration in diabetic retinopathy. The central hypothesis for the proposed research is that there is a previously unrecognized upstream molecule that triggers the pro-inflammatory responses mentioned above and mediates neuro-vascular degeneration in diabetic retinopathy. Finding that a single molecule controls various cellular responses involved in the pathogenesis of this disease would be significant because it would suggest that targeting a single molecule would impair multiple pro-retinopathy factors. In the first specific aim we will characterize the regulation of pro-inflammatory responses in retinal microglia, Muller cells and endothelial cells. This will be accomplished using immunological assays and gene transfer approaches that block specific signaling proteins. In addition, we will test whether a novel approach to deliver molecules intra-cellularly can be used to block signaling that controls pro-inflammatory responses in retinal cells. Using similar methodologies, in the second specific aim we will characterize the regulation of neuronal and endothelial cell death caused by these pro-retinopathy responses. Using an animal model of diabetic retinopathy in wild-type and knock-out mice we will evaluate the in vivo effects of regulation of inflammation on the development of diabetic retinopathy. The proposed work may lead to new strategies to treat diabetic retinopathy.